The long-term goal of this proposed research project is to establish a high-resolution noninvasive functional imaging technology, which promises to have great potential in clinical applications guiding presurgical planning in epileptic and tumor patients, who will undergo cortical resections. The specific goal of the proposed research project is to validate a high-resolution cortical imaging technique (CIT), which promises to reconstruct electrocorticogram (ECoG) from noninvasive scalp electrical recordings and patients' magnetic resonance imaging (MRI), in patients undergoing neurosurgical procedures in a clinical setting. To accomplish this goal, the following specific aims will be addressed: (1) Evaluation and Optimization of CIT by Computer Simulations: We will systematically evaluate the performance of the CIT through a series of numerical experiments, and optimize parameters of importance and numerical strategies for the cortical imaging procedures. (2) Validation of CIT from Intracranial Recordings during Somatosensory Stimulation in Patients: We will undertake the first, to our knowledge, full-scale study to validate the CIT in 50 epilepsy patients undergoing surgical evaluation. We will test the hypothesis that the CIT will be able to noninvasively identify and localize the central sulcus separating the sensory and motor cortex in the SEP paradigm. (3) Validation of CIT from Intracranial Recordings during Epileptic Seizures in Patients: We will directly test the clinical applicability of CIT to noninvasively identify cortical regions displaying epileptic activity, through intra- and extra-cranial recordings in 50 epilepsy patients undergoing surgical evaluation. We will test the hypothesis that the CIT will be able to noninvasively and reliably reconstruct site of seizure onset and locations of inter-ictal spikes, and significant characteristics of spatial maps of ECoG. Determining the location of the epileptogenic foci is of crucial significance for the successful surgical treatment of intractable epilepsy. The established clinical practice is to use ECoG recordings obtained by subdural electrode arrays, which represents risks and expenses to the patients and healthcare. The present application addresses the practical problem of developing noninvasive means of reconstructing ECoG from scalp EEG recordings and MRIs of the patients. The studies addressed in this application may establish CIT as a clinically useful tool aiding neurosurgical planning in epilepsy patients.